Contact assembly for cutouts



Dc. l0, 1940. 1 ,.P sol-[LES 2,224,614

CONTACT ASSEMBLY Fon cUToUTs Filed Nov. 26, 19:57

GMS TAN T C URRE N T THA NSF'OHNER Invenbov: s 3 Lerog F. Sohles,

Patented Dee. 1o, 1940 UNITED STATES PATENT OFFICE Leroy P. Sohles, Pittsfield, Mass., assignor to General Electric Company, a corporation ot New York Application November 26, 1937, Serial No. 176,448

12 Claims.

This invention relates t an improved contact assembly for an electrical cutout. Y

The cutout employs two circuits, the upper one of which includes contacts connected in a power line and the lower one o! which includes contacts connected to a loop line of lamps, or the like. The contacts oi.' the two lines are interconnected by spaced conductors placed in the contact cover and thus the loop line may be connected to the power line by closing the cover and disconnected by opening the cover. It will be apparent that as the cover is opened and closed the contacts at the power line will be similarly opened and closed and since the power line may carry heavy currents arcing at these contacts will take place as the current is interrupted.

One of the objects of this invention is to provide means to prevent this arcing and to this end an improved contact assembly is provided in the form of pivoted contactblades having bosses thereon which coact with the spaced conductors on the cover to form a circuit prior to separation of the contact blades, thereby preventing arcing between the contact blades as they open.

Another object o! the invention is to provide spring means which are adapted to move the contacts toward each other and at the same time hold the contact assembly in mounted position by coaction with the body of the cutout housing.

The switch assembly of the invention may be manufactured as a unit and inserted into the cutout housing. In such position it acts to prevent arcing at the power line contacts and there- 35 by greatly increases the life of the cutout.

In the drawing, Fig. l is a cross-sectional view of the cutout with the improved contact assembly shown employed in the upper contact; Fig. 2 is a plan view partly in cross-section of the con- 40 tact assembly in open position; Fig. 3 is a view of the contact assembly in partially closed position; Fig. 4 is a plan view of the contact assembly in fully closed position, and Fig. 5 is a dia- 45 grammatic view of the cutout employedlin a series line connected to a loop circuit.

Referring to the figures, the cutout C comprises a porcelain housing I0 with a cover II pivoted thereto at the lower end. The housing contains upper and lower contact assemblies which are mounted upon insulating blocks or bases I2 resting in recesses I2* formed in the housing'I III. The lower contact is shown in the form of phosphor bronze spring blades I3 but, if desired, the lower contact may take the form of the improved assembly shown in the upper contact which is now to be described.

The upper contact assembly comprises a base I2 carrying spaced terminals Il and I5 provided with screws I5* to clamp the power line leads to the terminals. The terminals Il and I5 have mounted thereon supporting arms I9 and I1 in the form of U-shaped metal strips carrying at their outer ends pivots I8 and I9 in the formV of bolts uniting the respective arms of each U- shaped strip. The pivots are adapted to rotatably support contact arms 2II and 2| having contact faces 22 and 23 at their outer ends, respectively, the pivot bolts extending through bifurcations formed in the ends of the arms. 'I'he bifurcated portions of contact arm 20 are shown at 2lia and 20b by Fig. l. The contact arms extend inwardly from the pivots between the U-shaped strips and are formed with bosses 24 and 25, respectively; the contact arms are electrically connected to the terminals Il and I5 by braided conductors 26 and 21, which are fastened to the bosses at one end and soldered to the terminals at the other. A spring 28 is mounted on each of the pivot bolts I9 and I9 between the bifurcated portions of the contact arm and is adapted to force its respective contact arm 20 or 2I toward the other in engaging relationship by means o! the spring ends 28a which engage the contact arm. The contact arms are thus retained normally in closed position under the action of springs 28. The other end 28h of eachy spring engages a recess, as shown at 29, whichv is formed in the cutout housing III. By this construction the springs are tensioned between the arms and the recesses and the reaction ofthe spring arms 2i!b upon the pivot bolts I8 and I9 is utilized to hold the contact assembly in position with the base I2 seated in the recess I2. In addition to holding the assembly tlrmly against the rear wall of the housing, the ends 28b of the springs coact with the recesses 29 to prevent lateral displacement of the assembly. In the construction shown the springs not only act to close the contacts, in the manner shown by Figs. 3 and 4, but also act to hold the switch assembly in position in the housing recess.

The cover Il is formed with a contact member or spacer A which is adapted to be inserted between the contactl arms 20 and 2l to open and close them against the action of springs 28 as the cover is closed or opened. The spacer or contact member comprises contact arms 30 and 3| of copper, or the like, which are spaced from each other by an insulating insert 32 of porce- 2,224,014 4 v v Y lain, or the like. 4 While the arms 30 and 3| are 'niearms of contact I3 likewisecloseforminga shown separated by the insert 32, it is obvious 4closed circuit through the loop. Clolure of the that the insert may be omitted and the arms insulated from each otherby an air gap; in such case the arms are made sumciently rigid to maintain the air gap. The contact arms 35 and vand25formedonthecontactarmsandhenice 3| are formed with depressedportions 33 and 3l, -respectiveli7, similar depressed portions being likewise formed in the porcelain insert. The depressions are adapted to'receive the bosses 24 they act to hold the spacer in engagement with .the contact arms. The outer ends of the contact Y arms 30 and 3| are inclined toward each other to form beveled prongs 35 and 38, which engage the bosses to separate the contact arms upon insertion of the spacer, while the end of the porcelain insert projects beyond the -prong ends to form an insulating separating element 31. A

contact B which may be similar in formto contact A is placed on the lower end of the cover II to coact with contacts I3 and separate them when the cover-.is closed. The contact arms of the respective upper and lower contacts A- and B formed on the cutout cover are interconnected on each side of the insulating spacing elements 32, i. e., the upper and lower contact arms 3II are connected together by a strip 38 of cOlDDer. or the like, while a similar strip 38 interconnects the upper and lower contact members 3I.

The manner in which the cutout operates will lno vv be described. In Fig. the cutout is shown to the power line. If it is desired to disconnect the loop line from the power line the cutout cover is pulled open thereby retracting the conductor strips 38 from engagementwith the contacts per mitting the contacts 'I' and l, as well as the contacts 2 and 3, to close. Mating of contacts I and 4 prevents interruption .of current in 'the series power line, while the loop circuit is now isolated from the series line and closed by mating of contacts2and3.

The improved cutoutshown by Figs. 1 to 4, inclusive, is placed in.,a series line in the manner illustrated by the diagrammatic .showing of Fig. 5 with the terminals Il and I5 connected to a power line, and with the'. terminals of the lower switch assembly I3 connected to a. loop line. Current from a constant current transformer now enters terminal Il passes-through flexible conductor 26, arm 25, boss 2l, contact arm 38, strip 38, contact B to contact I3 on one side of the loop line, thence around the loop line to the corresponding contact I3, contact B, strip 38, contact arm 3I, boss 25, arm 2l, conductor 2I,L to terminal I5. To disconnect the loop line from the series line the cover II is pulled open so that contacts A and B on the cover are disconnected from arms 23^2I and contact |3, respectively, and current can no longer reach the loop throughstrim 38. When the cover is opened and contact A is withdrawn from between the contact arms 2li and 2I, the arms close together under the action of springs 28 so that faces 22 and 23 make contact with each other and current .passes directiy.from' terminal I4 to terminal I5.

ing of current in the loop. T he improved con- 1 tact structure herein described is designed to prevent such. arcing and the manner in which 'this result is attained maybe best understood from a consideration of Fig. 3 in which the upper cover contact A is shown in partially nested position withthe contact arms 20 and 2I. sov that it may l either be inserted between the contacts or retracted therefrom. In this mid-position the Ybosses and25onthecontactarmsareinintimate contact with the inclined Prngs 35 and 38 \\of the contact members. and 3| and the contact faces 22 and 23 are in engagement. Accordingly, current.from'terminal Il can reach terminal I5 by two passages, viz: across faces 22 and 23, or acro the bosses 2l and 25 through the medium of the prongs 35 and 38 and the loop circuit. If now the cover is to be opened andthe loop circuit disconnected from the power line'by -retracting contact A from between the contact f arms, an arc will not be formed between prongs 35-33 and bosses 24-25 because faces 22 and 23are in engagement to carry the current-along the power line. Onthe otherhand. if the cover 'is to be closed to connect theloop line by further insertion of the contact A between the contact arms an arc will not be formed upon separation of the'faces.22.-23 becausesome of the current will be carried through the loop line by means of the prongs -38 which contact the bosses 2&-25 before the contacts 22-23 are separated.

When the cover is in closed position the bosses 24 and 25 are seated in the depressions 33 and 3l, respectively, and thus the cover is latched in closed position. 'Ihe springs 28 react upon the arms 2l and 2| sol that thebosses exert a substantial gripping force upon the cover contact A holding the cover firmly in closed position.

' It will be seen that the improved switch structure functions not only as a means to prevent arcing but also functions to latch the cutout cover in closed position. When the cutout cover is opened all connections between the power line and the loop line are absolutely open. This permits repairs to be made upon the loop line with perfect safety and at' the same time continuity of the power line is not impaired. l

What I'claim as new and desire to secure b Letters Patent of the United States is:

1. In a cutout switch, a housing, a'base adapted to be mounted in said housing, contact arms pivoted to said base, and spring means securing said base in said housing and adapted to move said contact arms into engagement.

' 2. In a cutout switch, a housing, a base adapted to be -mounted in said housing, contact arms pivoted to said base, a spacer element adapted to pivoted to said base, a spacer-element adapted to 15 nest with said arms, and spring means mounted on said pivots and engaging said arms and housing to hold said base in mounted position and said spacer in nested relationship.

5. In a cutout switch, a housing, a cover for said housing, a base adapted to be mounted in said housing, contact arms pivoted to said base, said arms having bosses formed thereon, a spacer mounted on said cover and having depressed portions adapted to receive said bosses, and spring means mounted between said arms and housing and adapted to hold said base in said housing and said bosses within said depressed portions.

6. In a cutout switch, a housing, a cover for said housing, a base adapted to be mounted in said housing, contact arms pivoted to said base, spring means mounted on said pivots and engaging said arms and housing to hold said base in mounted position, a spacer element mounted on said cover and adapted to nest with said arms when said cover is closed and hold them in separated position, and latching means cooperating with said spring means to hold the spacer in nested relationship and said cover in closed position.

7. In a switch assembly, a base, opposed contact arms pivotally mounted on said base and having contact faces at their outer ends, said contact arms having projecting means, spring means acting to pivot said faces into contact with each other, and a spacer element adapted to separate said contact arms against the action of said spring means, said spacer element comprising opposed contact blades insulated from each other and formed with beveled portions, said beveled portions coacting with said projecting means to form a circuit therewith before separation of said contact faces upon insertion of said spacer between said arms whereby arcing at said contact faces is prevented.

8. In a switch assembly, a base, opposed contact arms pivotally mounted on said base and having contact faces at their outer ends, said contact arms having projecting portions, spring means acting to pivot said faces into contact with each other, and a spacer element adapted to separate said contact arms against the action of said springs, said spacer element comprising opposed contact blades insulated from each other and formed with beveled portions, said beveled portions coacting with said projecting portions to form a circuit therewith before separation of said contact faces upon insertion of said spacer between said arms whereby arcing at said contact faces is prevented, said spacer having depressions formed therein, said projecting portions coacting with said depressions to latch said spacer between said arms.

9. In a switch assembly, a base, opposed contact arms pivotally mounted on said base at one end and having normally interengaging contact faces at the other end, said contact arms being provided with projecting portions substantially intermediate their length and a spacer element having conducting blades insulated from each other and contacting said projecting portions while said contact faces are in engagement to form a circuit prior to separation of said contact faces as said switch is opened by insertion of said spacer between said arms.

10. In a switch assembly, a base, terminals mounted on said base, substantially U-shaped supporting arms mounted on said base in spaced relation, contact arms having bifurcated portions, pivots mounting said bifurcated portions, springs mounted on said pivots and urging said contact arms towards each other, flexible conductors connecting said contact arms to said terminals, and means acting to open said contact arms against the action of said springs.

11. In a switch assembly, a base, fixed supporting arms extending outwardly from said base in spaced relation to each other, contact members pivotally mounted on the outer ends of said arms, said contact members extending inwardly toward said base and having contact surfaces adapted to engage one another, spring means mounted on said arms normally biasing said contact members into engagement with each other, and means acting to open said contact arms against the action of said spring means.

12. In a switch assembly, a base, U-shaped supporting members extending outwardly from said base in spaced relationship, contact arms pivotally mounted on the outer ends of said members and movable between the arms of the U formed by said supporting members, spring means urging said contact arms toward each other, ilexible conducting means connected to said contact arms and adapted to be connected to an electric circuit, and means acting to open said contact arms against the action of said spring means.

LEROY P. SOHLES. 

